1. Field of the Invention
There is known at present a wide variety of coil winding machines, with even considerably different characteristics as far as working and productive capacity.
These include first of all coil winders with a revolving turret, an example of which is described in DE-PS-2.322.064 filed by the same Applicant. In a machine of this type, the coils are mounted on spindles radially projecting from a revolving turret and this latter has a rotary stepped motion, so that the single coils are moved forward through successive working stations, for example at least one loading station, a winding station and an unloading station, as well as one or more supplementary working or finishing stations. When the coils are unloaded, they are substantially finished and ready for use.
It is important to note, in order to fully understand the present invention, that in machines of this type the coil core is held stationary and the winding is carried out by a winding unit with rotary flyer, which is not only adapted to rotate about the coil core, performing at the same time an axial movement (X axis) to distribute the wire around said core, but also to perform transversal (Y axis) and vertical (Z axis) movements in order to carry out supplementary operations, as for example the twisting of a wire end around a coil terminal.
To perform the above movements, the rotary flyer is first of all mounted on a spindle revolving about the axis X and rotated by a motor of its own, the flyer unit being moreover mounted on slides adapted to perform said movements along the three axes X, Y, Z. Such movements are generally produced by numerically controlled D.C. motors, according to an increasingly developing technology.
Another type of coil winding machine is the so-called "on-line machine", wherein the coils are supported by a plurality of spindles with parallel axes, mounted on a bed and performing a simple high-speed rotary motion. With each spindle there cooperate corresponding flyers, adapted to perform the main wire distributing motion during coil winding, as well as a more complex motion for twisting for example the wire ends on the coil terminals, just before winding starts and after it has ended.
It is to be understood that, in this case, the rotary motion about the axis X is performed by the spindle carrying the actual coil core, while the flyer merely performs the movements along axes X, Y and Z, as specified heretofore.
2. Description of the Prior Art
Machines of this type are widely known, for example, from DE-A-2632671 and DE-A-3049406, as well as from IT-B-1.196.312 filed on Oct. 26, 1984, by the same Applicant. These machines are planned to wind up coils in a relatively simple way and with a high number of turns, at high production speeds.
A still further type of coil winding machine is the "bench machine", which can be for example of the type described in EP-A-182.177 filed by the same Applicant: in this machine, the coils are mounted on rotary spindles, while the wire is fed by flyers adapted to perform movements along the three axes X, Y and Z--similarly to what happens in the previously mentioned on-line machines--so that the operator merely has to carry out the loading and unloading of the coils.
A problem which is particularly felt in the aforecited machines--for example of IT-A-1.196.312 or of EP-A-182.177--actually concerns the automatic loading and unloading of the coils on the winding spindles. The known devices allowing to perform these operations are quite complicated, oversized and costly: they must in fact generally comprise gripper means moving at least along two axes, that is, at least along the X axis, so as to draw close to and away from the spindle supporting the coil, and at least along another axis--for example the Z or the Y axis, or a turnover axis perpendicular to the X axis--so as to replace a filled and finished coil by an empty coil core.
These known automatic loading and unloading devices, as well as being complicated and costly, are also difficult to mount--due to their large dimensions--onto a coil winder being used as a working station of a plurality of stations forming part of an automatic production line.